One aspect of the invention relates to a winding arrangement with at least one multi-layered wound body comprising a large number of windings of at least one winding band and an optical waveguide passed through the wound body or introduced into the wound body.
Such a winding arrangement may be used for example in an optically monitored electrical device in the area of electrical power generation and distribution. The electrical device may in this case be designed as an electrical generator or else as an electrical transformer. Such an electrical device represents a very expensive and long-term investment. Its failure may entail very high costs. Therefore, the use of a diagnostic system, which may in particular also comprise an optical measuring device, is increasingly being considered for the early detection of defects, such as for example overheating or electrical flashover. The structural design of the device used in electrical power generation is currently already optimized in many varied respects. In particular, a very compact form of construction has by now been achieved, a design in which a sensor with a relatively great space requirement cannot be accommodated in the active part of the electrical device without extensive redesigning of the electrical device. What is more, there is often a great potential difference between different parts of such an item of equipment, possibly reaching values of up to several 10 kV. Therefore, an electrical sensor often cannot be used in such an electrical device. Far better suited on the other hand is an optical sensor, in particular a fiber-optic sensor. This is because the latter has a very small overall size. Moreover, due to the dielectric feed in the form of an optical waveguide, even a great potential difference can be bridged without any problem.
On the basis of these advantages, an optical measuring device for monitoring an electrical device used in electrical power generation and distribution has already frequently been described. For instance, the general article “Fiber Sensors for Industrial Applications” by M. Lequime, 12th International Conference on Optical Fiber Sensors, 10.28-31.1997, pp. 66-71, discloses an optical measuring device for an electrical generator. In the case of this measuring device, the vibration spectrum and the temperature of the coolant used for cooling an electrical conductor are sensed by an optical sensor.
An optical measuring device is also described in the specialist article “A Temperature Optical Fiber Sensor Network: From Laboratory Feasibility to Field Trial” by H. Fevrier et al., 8th Optical Fiber Sensors Conference, 01.29-.31.1992, pp. 262-265. Here, a fiber-optic sensor network serves for virtually distributed temperature sensing in a 250 MW generator.
Another optical measuring device for sensing the temperature in a 900 MW turbo generator is known from the specialist article “Industrial Prototype of a Fiber-Optic Sensor Network for the Thermal Monitoring of the Turbogenerator of a Nuclear Power Plant—Design, Qualification, and Settlement” by C. Meunier et al. in Journal of Lightwave Technology, Vol. 13, No. 7, July 1995, pp. 1354-1361. The optical temperature sensors in the case of this measuring device are adhesively attached to a water connection element which is located in the outlet region of the coolant line from an electrical conductor.
In the case of these known optical measuring devices, in each case only indirect measured variable acquisition is performed, or no specific details are given on how the feeding optical waveguide is brought up to an electrical conductor to be monitored and the optical sensor is attached there. Since, during operation, the conductors of such an electrical device often carry a very high electrical current, which may assume values up into the kA range, the conductor temperature is an important measured variable for the diagnosis of the device. To obtain a measurement result which is as accurate as possible, it is favorable to position the optical sensor, and consequently also the feeding optical waveguide, as close as possible to the current-carrying conductor. Since, for reasons of insulation, the electrical conductor is often surrounded by an electrical insulation in the form of a wound body, the requirement for measured variable acquisition that is as direct as possible leads to the optical sensor and also the part near the sensor of the feeding optical waveguide being arranged in the interior of the wound body, to be more specific between the electrical conductor and the wound body. In the case of the known optical measuring devices, on the other hand, this requirement does not exist on account of the only indirect measured variable acquisition. In principle, contact that is as direct as possible between the electrical conductor and the part of the optical waveguide near the sensor is not envisaged.
In EP 0 753 130 B1, an optical waveguide embedded in a multi-layered composite structure is described. A force to be detected is transmitted through the disclosed special composite structure to the fiber-optic sensor. How precisely the optical waveguide is led out of the composite structure is not revealed by EP 0 763 130 B1.
WO 95/13994 A1 discloses a series of types of optical waveguide which have a protective layer in various embodiments. Special suitability of the individual types of optical waveguide for use in one of the measuring devices described above is not specified.
The object maybe achieved by providing a winding arrangement with at least one multi-layered wound body comprising a large number of windings of at least one winding band and an optical waveguide passed through the wound body or introduced into the wound body, with which arrangement guidance of the optical waveguide through the wound body is possible.
To achieve the object, a winding arrangement corresponding to the features of patent claim 1 is specified.
The winding arrangement comprises at least one multi-layered wound body comprising a large number of windings with at least one winding band, an optical waveguide passed through the wound body or introduced into the wound body, the optical waveguide being wound into the wound body in the area where it passes through or is introduced and comprises, at least in the area where it passes through or is introduced, a light-guiding fiber and a protective layer applied thereto, which protective layer comprises a material for a protective layer with a modulus of elasticity of at most 2.5 GPa.